linux-kernel - [PATCH 07/11] fs: Allow CAP_SYS_ADMIN in s_user

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Date:   Fri, 22 Dec 2017 15:32:31 +0100
From:   Dongsu Park <dongsu@...volk.io>
To:     linux-kernel@...r.kernel.org
Cc:     containers@...ts.linux-foundation.org,
        Alban Crequy <alban@...volk.io>,
        "Eric W . Biederman" <ebiederm@...ssion.com>,
        Miklos Szeredi <mszeredi@...hat.com>,
        Seth Forshee <seth.forshee@...onical.com>,
        Sargun Dhillon <sargun@...gun.me>,
        Dongsu Park <dongsu@...volk.io>, linux-fsdevel@...r.kernel.org,
        Alexander Viro <viro@...iv.linux.org.uk>
Subject: [PATCH 07/11] fs: Allow CAP_SYS_ADMIN in s_user_ns to freeze and thaw filesystems

From: Seth Forshee <seth.forshee@...onical.com>

The user in control of a super block should be allowed to freeze
and thaw it. Relax the restrictions on the FIFREEZE and FITHAW
ioctls to require CAP_SYS_ADMIN in s_user_ns.

Cc: linux-fsdevel@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Signed-off-by: Seth Forshee <seth.forshee@...onical.com>
Signed-off-by: Dongsu Park <dongsu@...volk.io>
---
 fs/ioctl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ioctl.c b/fs/ioctl.c
index 5ace7efb..8c628a8d 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -549,7 +549,7 @@ static int ioctl_fsfreeze(struct file *filp)
 {
 	struct super_block *sb = file_inode(filp)->i_sb;
 
-	if (!capable(CAP_SYS_ADMIN))
+	if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
 		return -EPERM;
 
 	/* If filesystem doesn't support freeze feature, return. */
@@ -566,7 +566,7 @@ static int ioctl_fsthaw(struct file *filp)
 {
 	struct super_block *sb = file_inode(filp)->i_sb;
 
-	if (!capable(CAP_SYS_ADMIN))
+	if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
 		return -EPERM;
 
 	/* Thaw */
-- 
2.13.6